Atomic Fission

On February 11, 1939, the journal Nature published a theoretical
paper on nuclear fission. The term was coined by the authors Lise Meitner and
Otto Fritsch, her nephew. They knew that when a uranium nucleus was struck by
neutrons, barium was produced. Seeking an explanation, they used Bohr's "liquid
drop" model of the nucleus to envision the neutron inducing oscillations in a
uranium nucleus, which would occasionally stretch out into the shape of a
dumbbell. Sometimes, the repulsive forces between the protons in the two bulbous
ends would cause the narrow waist joining them to pinch off and leave two nuclei
where before there had been one. They calculated the huge amounts of energy
released. This was the basis for nuclear chain reaction and was recognized by
the U.S. government as a potential weapon which led to the establishment of the
Manhattan Project. Meitner was invited to work on the project but
refused.